ALWI was retained by the engineering firm of Daft, McCune, Walker (DMW) to evaluate, rehabilitate, redevelop and re-equip two existing production wells at the Jefferson School, located in rural Frederick County, Maryland.

Three wells exist, and had been plagued by excessive particulates and turbidity, which decreased efficiency and increased treatment costs. Our hydrogeologists identified the root cause of these conditions to be excessive drawdown during pumping cycles, which caused naturally-present iron and manganese to precipitate and clog fracture zones, pump impellers and treatment equipment.

Initially the raw water possessed abundant black particulates and the apparent yields of the wells had declined, one markedly so. We came to select two wells for rehabilitation, redevelopment, testing and reconnection. We determined that a third well was directly connected to same aquifer (i.e., did not offer supplemental water) and we judged its poor water quality to be an artifact of its initial construction. We recommended that this third well not be relied upon or invested in, and ultimately, that it be abandoned and sealed.

Focusing on the two selected supply wells, we designed and executed a step-wise program to assess the underlying cause of these initial conditions, to rehabilitate and restore initial yields and quality, and to provide a lasting remedy which included longer run-times with lower-capacity pumps set at shallower depths.  

We then verified the success of the rehabilitation and redevelopment work through stringent test pumping and sampling. Subsequent laboratory analyses confirmed potability but also the continued, natural presence of dissolved iron and manganese which are characteristics of the local geology.  

Jointly we and DMW then specified and provided replacement permanent pumps and related treatment infrastructure.